The Android Army Knife is composed of an “applet launcher” and a set of applets. Note: depending on the hardware capabilities of your device, some tools may not be available

Main application
The main application shows you the tools available. You can think of it like a virtual folder.
Like every other tool, the main application has his own menu that allows you to:

Chose if the main app will be closed after you start a tool. If you choose to keep the main app running, then as soon as you close the selected tool, you will land back to the main app

Change to background color

Open the about page

Access to this site’s help, FAQ and changelog pages

Report a bug to us

Exit the application

Flashlight
Flashlight allows you to see through the darkness. It does it by using the camera LED as a torch.
Optionally, if the camera LED is not available, it can display a totally white screen with brightness set to 100%.
You can turn on/off the light using the volume buttons too.
Note: not all devices are supported. About this topic please check the FAQ.
When the device’s screen is used as flashlight, you can change the light intensity by swiping up or down, to increase or reduce it respectively.
Starting from version 1.2 you can change the screen color to red, green, yellow, blue, or one of two customizable colors.

Unit Converter
This tool is an easy to use unit converter that tries to minimize the number of touches required to calculate the answer.
Just:

insert the number to convert (ex: 20)

select the category (ex: Temperature)

select the starting unit (ex: Celsius)

then you will see a list of units converted (20 degrees Celsius converted in Fahrenheit, kelvin and Rankine)
Note: because this app doesn’t require permissions to access the network, the currencies conversion is not available.

Timer
This tool implements a multi (up to 4) timer. It can be used as a classic “kitchen timer”. While one or more timers are running, you can use other apps or put the device on standby status.
Note: when the timer expires, this tool makes a sound using the Android standard notifications system (you can disable it and/or enable vibration from the tool’s menu). If your device has audible notifications disabled, the timer won’t be able to make sounds!. Please test it before using and – if required – have a look at the system menus.

Stop watch
It’s a classic stop watch with partial lap times.
You can start/stop/lap it using the volume buttons!

Compass
If your device has a magnetic sensor this tool let you find your way home when you’re lost
Because not all devices work as intended, if you have problems, please have a look at the FAQ.

Bubble level
Sometimes you need to make a shelf perfectly flat. This applet is your friend, provided you previously calibrated it
In order to calibrate it, please put your smartphone on a perfectly horizontal surface, then start the bubble level, select the “calibrate” menu option and press OK (making sure you do not move the device). In around 5 seconds your level will be calibrated!

Calculator
A classic scientific/standard calculator with a customizable number of significant digits. If you don’t like your device’s default calculator or it lacks some features, this applet is here for you.

Magnifying glass
Since version 1.2
Did you notice that by selecting macro mode and zooming 100% your device’s camera can be used as a simple magnifying glass? This app gives you a fast and easy to use magnifying glass, provided your device has a camera with zoom and macro mode.
The five keys on the bottom let you take a snapshot, light the camera LED (if your device has one), focus, zoom in and zoom out.
You can zoom in/out by swiping up or down too and focus by double tapping on the screen.
Enjoy your magnifying glass.

Mirror
If a front camera is available and you’re running at least Android version 2.3, this tool transforms your device into a simple mirror.
In case of darkness, you can illuminate your face by clicking the “light” button.

Ruler
The ruler app displays a ruler on screen.
It’s not an interactive app (apart from the calibration function): all you have to do is to put the object you want to measure near to your device’s screen, just like an ordinary ruler.

For some devices, the ruler starts incorrectly calibrated. Please don’t blame the app: some devices give you wrong measurements for their screens. For instance some Motorola devices show measurements three times larger than they should. That’s where the calibration function comes handy. However, if you want to have the maximum precision, please calibrate it anyway 😉
It can be calibrated by invoking his own menu: in order to calibrate, put a real ruler on top of the device’s screen and swipe up or down until the two scales match.